Further to Bruce a few years ago a guy had a needle fall off his electric
vario and he was actually happy to keep flying that week as it made him
listen to the audio. He still had his digital averager which was the only
thing he wanted to look at!!
Ian McPhee
----- Original Message -----
From: "Bruce Taylor" <[EMAIL PROTECTED]>
To: "Discussion of issues relating to Soaring in Australia."
<[email protected]>
Sent: Friday, November 17, 2006 9:36 PM
Subject: Re: [Aus-soaring] varios(was FLARM maths)
Hi All,
I was imagining I might be able to stay silent, but I can't help myself...
Please, no offence to Mike or any others, it is just that we all see
things slightly differently, thank heavens.
I don't think I ever watch the vario needle while flying. I would very
happily fly at any level with a good audio and a large, easily read
digital averager set high on the panel, and pretty much nothing else. Soon
I plan to fly some comp days with everything else covered up, just to see
whether I really do ignore it, but I have had a number of people flying in
the back seat while I am in front comment on the fact that I almost never
look at the panel.
I prefer my audio to have a single tone, and find no need for any
indication of whether I am in rising air that is above or below my
Macready setting. I simply want to know if I am going up, or if I am not.
I also do not use relative netto during the cruise, but this is a very
personal choice. This audio MUST be as close to perfectly compensated as
is possible with the system that you are using. I have to say that very
few gliders I have borrowed/stolen have a vario that really works. And I
have to agree totally with Mike - if the vario signal is coming from one
source, then make it a good one, and if it is coming from two sources,
pitot and static, then give it a good chance of working and keep the lines
from both as close to the same length as you can. This doesn't have to
cost heaps of money. Work on the KISS principle...
The decision to stop and climb in any particular bit of rising air comes
from other sources, primarily the structure of the thermal that is felt as
you fly into it, much more than any peak vario indication. Usually you
find that a well-structured thermal will produce a better bottom-to-top
average than one which shows strong gusts and high peak readings as you
approach it. As you are arriving at the edge of a thermal is not a good
time to be watching the panel, for a lot of reasons.
I have taken too much space already... back into my box.
BT
----- Original Message -----
From: "Mike Borgelt" <[EMAIL PROTECTED]>
To: "Discussion of issues relating to Soaring in Australia."
<[email protected]>
Sent: Thursday, November 16, 2006 1:17 PM
Subject: Re: [Aus-soaring] varios(was FLARM maths)
At 06:46 PM 14/11/2006, David Griffiths wrote:
I am impressed
I did not even know that this type of gear was available.
Is this all prototype stuff or is it in production?
You might like to look at the B500 on our site at
www.borgeltinstruments.com
Australian designed and manufactured, sold worldwide.
Before getting too excited about varios without visual indicators people
might like to consider how they decide whether to turn in a particular
thermal that is encountered. The vario pointer isn't the only thing but I
bet it is an important part of your decision. Relative netto was designed
to help with this - see our website for details if you don't know what
relative netto does(it is in articles).
Changing the audio at the MacCready setting as we do in the B500 and B50
lets you know to look at the vario but for reasons explained by John
Cochrane in his paper and nearly 40 years ago by Anthony Edwards, you fly
at Macready settings that are quite low compared to the actual rates of
climb you get so you might not make the decision to turn just based on
that audio change.
Likewise when picking a best path through the air, particularly when
streeting, including the vario pointer in your scan is important. To be
really useful here the vario pointer should be high resolution too. We
rejected LCDs on the grounds that the pointer resolution was too coarse.
When working very weak lift the speed of response and resolution of the
vario itself becomes important. When working 5 knots at altitude a poor
vario will do. When at 600 feet over a paddock trying to avoid an
outlanding by working +/-0.5 knots you need all the help you can get.
With some vario technologies there are unavoidable speed of
response/resolution tradeoffs.
Lastly, Total energy is total energy whether it is done by a probe
providing suction below static pressure or whether you measure pitot and
static pressures and add them electronically to provide the same thing.
They both suffer from horizontal gust effects (see article on website) to
the same extent but the pitot/static scheme has some additional
problems - the pitot and static ports are more sensitive to yaw and
sideslip than the modern two hole TE probe is and you need to organise
the pitot and static signals to arrive at the same time at the instrument
to avoid undesirable transient effects.
Mike
Borgelt Instruments - manufacturers of quality soaring instruments
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
Int'l + 61 429 355784
email: [EMAIL PROTECTED]
website: www.borgeltinstruments.com
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